Measuring instruments conventionally used in the field of clinical tests are mainly large-sized automated devices and POCT (Point of Care Testing) devices.
Large-sized automated devices are installed in hospital clinical laboratories and commercial clinical laboratories and capable of testing samples of many patients for a large number of items (e.g., see Patent Document 1). For example, a large-sized automated device of Hitachi 7170 is capable of performing 800 tests per hour for up to 36 items. Thus, they contribute to higher test efficiency and are equipment suited for hospitals with a large number of examinees.
Meanwhile, POCT devices refer to devices used in clinical tests that are conducted in medical settings other than hospital laboratories and test centers, and include devices for use in home healthcare (e.g., see Patent Documents 2 and 3). Such examples include blood sugar sensors, pregnancy test drugs, ovulation test drugs, and HbA1c/microalbumin analyzers (e.g., DCA 2000 available from Bayer AG). These POCT devices are inferior in versatility to large-sized automated devices. However, they are capable of focusing on a marker substance specific to a disease and measuring the marker substance in a simple and prompt manner. They are thus effective for screening and monitoring examinees. Also, POCT devices are small and portable, can be introduced at low costs, and can be used by anyone without requiring particular expertise in operation.
Currently, there are many items measured in clinical tests. When a body fluid such as urine is used as a sample, the measurement methods are roughly divided into optical measurement type and electrochemical measurement type. The above-described conventional large-sized automated devices and POCT devices use either type of measurements for making measurements.
Recently, swelling medical expenses and an increasing number of patients with life-style related diseases have been imposing a burden on medical economy, thereby necessitating a reduction in medical expenses and suppression of increasing lifestyle-related disease patients. One fundamental solution of such problem could be Evidence Based-medical (EBM). EBM allows objective management of medical care according to individual patients' needs, and it is expected that practicing preventive healthcare will lead particularly to a reduction in the number of lifestyle-related disease patients, etc.
To establish and practice EBM, test information obtained from clinical tests is essential. Test information in EBM includes test results and solutions for patients based on the test results. “solutions for patients” refer to guidance on lifestyle such as diet control and treatment by medication. That is, in EBM, tests are conducted in order to allow those who are to receive medical care to “find their problems” and “make a decision on courses of treatment”. In order to provide safer and better solutions in EBM, it is necessary to clearly present problems to those who are to receive medical care. Hence, in clinical tests, it has become important to obtain the test results of a plurality of interrelated test items easily and promptly.
The above-described conventional large-sized automated devices are versatile and capable of testing a large number of items regardless of whether or not they are related to a disease. However, since such devices have a complicated structure, they are difficult to operate for those without expertise. Further, there is a problem in that it takes long time to obtain a test result so that it takes long time to feed back the result to the examinee. Also, although the POCT devices are superior in operability and capable of easy and prompt tests, they are unable to test a plurality of items, since they are measurement devices designed specifically for markers that are related to specific diseases.
Thus, there has been proposed a device for use in biochemical or clinical tests, which includes a cavity into which a liquid sample flows by capillary action. The cavity includes an electrode structure for measuring at least one electrical characteristic of the sample, and a reagent such as an antibody or enzyme capable of being released into the cavity. A wall of the cavity is transparent so that the cavity contents can be optically measured (e.g., Patent Document 4).    Patent Document 1: Japanese Laid-Open Patent Publication No. Hei 09-127126    Patent Document 2: Japanese Laid-Open Patent Publication No. Hei 07-248310    Patent Document 3: Japanese Laid-Open Patent Publication No. Hei 03-046566    Patent Document 4: U.S. Pat. No. 5,141,868